The Official World Golf Ranking, which is endorsed by the four major championships and the five professional tours which make up the International Federation of PGA Tours, is issued every Monday, following completion of the previous week's tournaments from around the world. This statistic is the average number of points earned per event in the last 104 weeks. These points are awarded based upon finish position as well as the strength of the field. The points are initially worth double their original value and decline gradually over this two-year period. There are 8 13-week periods and points decline by .25 times their value each period. (186)